AVR-Chat

> I'm also curious, but a cap IS a low pass filter.

Depends, series or shunt?  Big cap or small?

DLC

> Cat
> ----- Original Message -----
> From: "dlc" <dlc@frii.com>
> To: <AVR-Chat@yahoogroups.com>
> Sent: Monday, June 18, 2007 11:00 PM
> Subject: Re: [AVR-Chat] Using the ADC to measure the battery supply?
>
>
>> If the cap is across it then the ADC might not get the correct voltage
>> either.  The ADC relies upon charging a cap inside the module.  That
>> relies upon a certain target RC charge rate, that charge rate also must
>> not exceed the current capacity of the pin.  You are playing a finicky
>> game by using a cap to boost the inrush current to offset the RC time
>> constant.  It might work under some circumstances but since the ADC
>> modules specifically states that you should only be using slowly
>> changing signals on the circuit with low-pass filters that would tend to
>> contra indicate using a bypass cap I think.  Have you used such a
>> circuit successfully before?
>>
>> curious,
>> DLC
>>
>>
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